Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11C—STATIC STORES
  • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
  • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
  • G11C11/14—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using thin-film elements
  • G11C11/155—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using thin-film elements with cylindrical configuration
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11C—STATIC STORES
  • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
  • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
  • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11C—STATIC STORES
  • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
  • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
  • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
  • G11C11/165—Auxiliary circuits
  • G11C11/1653—Address circuits or decoders
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11C—STATIC STORES
  • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
  • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
  • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
  • G11C11/165—Auxiliary circuits
  • G11C11/1675—Writing or programming circuits or methods
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10B—ELECTRONIC MEMORY DEVICES
  • H10B61/00—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N50/00—Galvanomagnetic devices
  • H10N50/10—Magnetoresistive devices

Definitions

• the invention relates to a memory cell arrangement with at least one magnetoresistive element and a method for its production.
• a magnetoresistive element also called a magnetoresistive element, is understood in the technical field to be a structure which has at least two ferromagnetic layers and a non-magnetic layer arranged between them. Depending on the structure of the layer structure, a distinction is made between GMR element, TMR element and CMR element (see S. Mengel, Technology Analysis Magnetism, Volume 2, XMR Technologies,
• GMR element is used for layer structures which have at least two ferromagnetic layers and a non-magnetic, conductive layer arranged between them and which show the so-called GMR (giant magnetoresistance) effect.
• GMR effect is understood to mean the fact that the electrical resistance of the GMR element is dependent on whether the magnetizations in the two ferromagnetic layers are oriented parallel or antiparallel.
• the GMR effect is large compared to the so-called AMR (anisotropic magnetoresistance) effect.
• AMR effect is understood to mean the fact that the resistance in magnetized conductors is different in parallel and perpendicular to the direction of magnetization.
• the AMR effect is a volume effect that occurs in ferromagnetic single layers.
• TMR element is used in the specialist world for tunneling
• Magnetoresistance layer structures are used, the at least two ferromagnetic layers and one arranged in between nete insulating, non-magnetic layer.
• the insulating layer is so thin that there is a tunnel current between the two ferromagnetic layers.
• These layer structures also show a magnetoresistive effect, which is brought about by a spin-polarized tunnel current through the insulating, non-magnetic layer arranged between the two ferromagnetic layers.
• the electrical resistance of the TMR element depends on whether the magnetizations in the two ferromagnetic layers are aligned parallel or anti-parallel. The relative change in resistance is about 6 to about 40 percent at room temperature.
• CMR colossal magnetoresistance
• GMR elements to be used as memory elements in a memory cell arrangement.
• the memory elements are connected in series via read lines.
• Word lines run at right angles to this and are insulated both from the read lines and from the memory elements. Due to the current flowing in each word line, signals applied to the word lines cause a magnetic field which, with sufficient strength, influences the memory elements located thereunder.
• x / y lines are used which cross at the memory cell to be written. Signals are applied to them that are sufficient for re-agregation at the intersection. magnetic field.
• the Magne ⁇ t Deutschensraum m is changed one of the two ferromagnetic layers.
• the direction of magnetization m of the other of the two ferromagnetic layers remains unchanged.
• the direction of magnetization m of the last-mentioned ferromagnetic layer is held by an adjacent antiferromagnetic layer, which holds the direction of magnetization, or by the switching threshold for this ferromagnetic layer being different from that of another material or dimensioning, for example the layer thickness first mentioned ferromagnetic layer is enlarged.
• a storage element comprises a stack which has at least two annular ferromagnetic layer elements and a non-magnetic conductive layer element which is arranged between them and which is connected between two lines.
• the ferromagnetic layer elements differ in their material composition.
• One of the ferromagnetic layer elements is magnetically hard, the other magnetically softer.
• the magnetization direction m is switched over to the magnetically softer layer element, while the magnetization direction m is retained with the magnetically harder layer element.
• a further memory cell arrangement with ring-shaped memory elements based on the GMR effect has been proposed in WO 96/25740. They have layer elements made of two magnetic materials, one of which has a high and the other a low coercive force.
• two driver lines are provided, both of which run through the center of the ring-shaped GMR element. Switching the magnetization rungs ⁇ chtung takes place with the help of a magnetic field, which is induced by currents m the two driver lines.
• a current flows between the two lines between which the GMR element is connected, which current also flows through the storage element.
• the magnetic field induced by this current is used to change the direction of magnetization.
• both driver lines are ring-shaped through the center of the
• the invention is based on the problem of specifying a memory row arrangement with at least one magnetoresistive element which is insensitive to external magnetic interference fields, which is functional both for magnetoresistive elements with a TMR effect and with a GMR effect, and which functions in comparison with the prior art increased packing density can be produced. Furthermore, a method for producing such a memory cell arrangement is to be specified.
• the memory cell arrangement has at least one magnetoresistive element which has an annular cross section in a layer plane.
• the magnetoresistive element has layer elements which are stacked one above the other perpendicular to the layer plane.
• the use of a magnetoresistive element with an annular cross section increases the sensitivity to external magnetic
• the memory cell arrangement further comprises a first line and a second line, which intersect.
• the magnetoresistive element is arranged in the crossover area between the first line and the second line.
• the first line and the second line are in the intersection area arranged on different sides of the magnetoresistive element with respect to the layer plane.
• the first line and / or the second line have at least a first line component and a second line component.
• the first line component is aligned in such a way that a current component directed parallel to the layer level predominates, whereas in the second line component in the crossover area between the first line and the second line a current component directed perpendicular to the layer level predominates.
• the first runs parallel to the layer plane
• the second line portion crosses a plane parallel to the layer plane in the area of intersection between the first line and the second line.
• the first line and / or the second line are cranked perpendicular to the layer plane.
• the currents flowing through the lines designed in this way generate a magnetic field at the location of the ring-shaped magnetoresistive elements, which is suitable for remagnetizing the magnetoresistive elements during the writing process.
• Both the m of the layer plane of azimuthal (circular) magnetic fields of the vertical current components and the lateral, ie m of the layer plane of the parallel current components perpendicular to the longitudinal direction of the line of the parallel current components contribute to the magnetic reversal field.
• the current components parallel to the layer plane contribute to the remagnetization, because the first line portions of the first as well as the second line have different distances from the ring-shaped magnetoresistive element and therefore do not compensate each other there.
• the lines designed in this way make it possible to arrange memory cells which, compared to previous solutions, can be produced more easily and with greater packing density.
• the first and second lines crossing at the location of the memory element are sufficient for writing and reading.
• the memory cell arrangement can be implemented both with a magnetoresistive element based on the GMR effect and with a magnetoresistive element based on the TMR effect, since in contrast to the solution for producing the magnetic known from US Pat. Nos. 5,477,482 and 5,541,868 Switch panel no current is required across the magnetoresistive element.
• Both the first line and the second line preferably each have at least a first line component in which a current component directed parallel to the layer plane predominates and a second line component in which a current component directed perpendicular to the layer plane predominates. If the first line and the second line are wired in such a way that the current through the second line part of the first line and the current through the second line part of the second line flow in the same direction, the azimuthal magnetic fields of these currents overlap constructively and are amplified at the location of the magnetoresistive element. In this way, selective writing in memory cell fields is possible.
• the magnetoresistive element is connected between the first line and the second line, the stored information about the first line and the second line can be read out.
• the resistance of the magnetoresistive element is evaluated. This can be done by measuring the absolute resistance of the magnetoresistive element, by measuring the change in resistance when switching the magnetoresistive element or by comparing the resistance with an adjacent magnetoresistive element of known magnetization state. For reading out the saved Information, all methods for resistance evaluation of the magnetoresistive element are suitable.
• the magnetoresistive element preferably each has a first ferromagnetic layer element, a non-magnetic layer element and a second ferromagnetic layer element, the non-magnetic layer element being arranged between the first ferromagnetic layer element and the second ferromagnetic layer element.
• the magnetoresistive element can be based on both the GMR effect and the TMR effect.
• the use of a magnetoresistive element based on the TMR effect is preferred because of the greater resistance compared to a GMR element, the resulting lower power consumption and the usually larger magnetoresistance effect.
• the magnetoresistive element can be based on the CMR effect if the arrangement can generate the required magnetic switching fields.
• the first ferromagnetic layer element and the second ferromagnetic layer element preferably contain at least one of the elements Fe, Ni, Co, Cr, Mn, Gd, Dy, Bi.
• the first ferromagnetic layer element and the second ferromagnetic layer element preferably differ in terms of magnetic hardness and / or their layer thickness.
• the first ferromagnetic layer element and the second ferromagnetic layer element preferably have a thickness between 2 nm and 20 nm.
• the non-magnetic layer element contains in the case of the TMR
• the non-magnetic layer element preferably contains at least one of the substances Cu, Au, Ag and / or Al and has a thickness of between 2 and 5 nm perpendicular to the layer plane.
• the first ferromagnetic layer element, the second ferromagnetic layer element and the layer element have specific mecanici- parallel to the layer plane preference ⁇ have dimensions between 50 nm and 400 nm.
• the memory cell arrangement has a multiplicity of magnetoresistive elements of the same type, which are arranged in a matrix.
• a plurality of similar first lines and similar second lines are also provided.
• the first lines and the second lines cross.
• One of the magnetoresistive elements is arranged in the intersection between one of the first lines and one of the second lines.
• the first lines and / or the second lines each have alternating first line portions, in which a current component directed parallel to the layer level predominates, and second line portions, m in which a current component directed perpendicular to the layer level predominates. Since the ring-shaped magnetoresistive elements are almost magnetically decoupled, a high packing density can be achieved.
• both the first lines and the second lines each have first line components and second line components, so that selective writing is possible in the individual memory cells.
• the first line parts and the second line parts of one of the first lines and / or the second lines are arranged in such a way that the line in question has a strip-shaped cross section parallel to the layer plane.
• a space requirement of 4 F 2 can be achieved per memory cell, where F is the minimum structure size that can be produced by the respective technology, provided the width of the lines parallel to the layer plane and the distance between adjacent lines F are.
• m arise in the layer plane at the location of each ring-shaped memory Cherimplantations by constructive superposition of the vertical current components m the first and / or second lines an azimuthal magnetic field, which is primarily responsible for the magnetization of the ring-shaped magnetoresistive elements. Magnetic field contributions that result from the current components parallel to the layer plane lead to an asymmetry of the resulting magnetic switching field, which has a positive effect with regard to reduced switching field thresholds.
• the magnetoresistive elements are arranged in m rows and columns between the first and second lines, the layer plane being spanned by the center planes of the magnetoresistive elements.
• the direction of the rows and the direction of the columns run parallel to the layer plane, the direction of the rows crossing with the direction of the columns.
• the projections of the first line portions of one of the first lines onto the layer plane are each arranged between adjacent magnetoresistive elements of this row in such a way that the projections with respect to the connecting straight line through the magnetoresistive elements of this cell are alternately laterally offset.
• the projection of the first line portions of one of the second lines onto the layer plane is in each case arranged between adjacent magnetoresistive elements of one of the columns, the projection being arranged laterally offset with respect to a connecting line between the adjacent magnetoresistive elements.
• the projections of first line components adjacent to one of the lines onto the layer plane are arranged offset on opposite sides with respect to the respective connecting lines.
• the projections of the first lines and the second lines onto the layer plane are therefore not elongated rectangles, but rather wavy.
• two-fold symmetrical local azimuths are located at the location of the magnetoresistive elements caused mutal magnetic fields.
• the space requirement per memory cell is 9 F 2 .
• magnetic switching fields of higher namely two-fold symmetry m of the layer plane are generated at the location of the annular elements.
• This configuration preferably has the following features:
• the structures in the wave-like bands are repeated periodically, the wave-like bands swinging about a central longitudinal direction.
• the projection bands of the first lines intersect with those of the second lines in the "zeros" of the shaft bands, the middle longitudinal directions forming a right angle, but the bands run parallel to one another in sections.
• the zero point is the intersection of the pro tape with the respective central longitudinal direction.
• the ring-shaped magnetoresistive elements are arranged m of the layer plane at the intersections between the first and second lines m rows and columns.
• the first and second lines are bent perpendicular to the layer plane at the crossing points, so that at these
• the memory cell arrangement additionally has the following features:
• the period of the wave-like bands is 6F, their amplitude F / 2.
• the tapes have a minimum width and a minimum distance F perpendicular to their longitudinal direction.
• the projection bands of the first lines and the second lines run parallel to one another in segments of length F.
• the ring-shaped storage elements are arranged m on the layer plane at the intersections between the first and second lines m distances of 3F m rows and columns.
• a first line is produced on a main surface of a substrate in order to produce the memory row arrangement.
• the magnetoresistive element is formed which has an annular cross section in one layer plane.
• a second line is created which crosses the first line so that the magnetoresistive element is arranged in the crossing region.
• the first line and / or the second line are generated in such a way that they have at least a first line component, one parallel to the Layer plane directed Stromkomponenete predominates, and having a second line portion, where a m ne perpendicular to Schichtebe ⁇ directional current component predominates.
• the structuring of the first ferromagnetic layer, the non-magnetic layer and the second ferromagnetic layer is preferably carried out with one and the same mask.
• the ring-shaped, magnetoresistive element it is advantageous to use a self-aligned process.
• an opening is produced in a layer which is arranged on a main surface of a substrate, and a conforming layer is deposited over the flanks of the openings.
• Anisotropic scratching of the conformal layer creates an annular spacer on the flanks, which is used as a mask for the anisotropic structuring. If the opening is created with a dimension of F, magnetoresistive elements with an outer diameter of F and an inner diameter smaller than F can be produced in this way.
• the first line and the second line are preferably each produced in two steps.
• Lower segments of the first line or the second line are formed first, and then upper segments of the first line or the second line.
• the projection of the lower segments and the projection of the upper segments of the respective line onto the main surface of the substrate partially overlap, so that coherent and cranked first and second lines are produced.
• the second line components in which vertical current components occur at the layer level, arise in the overlapping areas of the lower and upper segments of the respective line. Parts of the lower segments or of the upper segments arranged in between represent the first line portions which run parallel to the layer plane.
• first metallization level which is usually referred to as metal 1 by experts
• second metallization level which is usually referred to as metal 2 in the art.
• the first lines of the cell array are preferably contacted via the first metallization level and the second lines of the cell array via the second metallization level of the periphery.
• the first line and the second line are preferably produced with the aid of Damascene-Techmk.
• a first insulating layer is deposited and structured with the aid of photolithographic process steps and anisotropic plasma steps (RIE) in such a way that it is removed in the region of the first metallization level of the periphery and the lower segments of the first lines of the cell field which are to be subsequently produced.
• a first conductive layer or a first conductive layer system is deposited and structured by a planarizing etching process, for example CMP. This forms the lower segments of the first lines and the first metallization level of the periphery.
• a second insulating layer is subsequently deposited and structured with the aid of photolithographic process steps and anisotropic etching steps in such a way that it is removed in the region of the first contacts of the periphery and the upper segments of the first line which are to be subsequently produced.
• the first contacts and the upper segments of the first line are formed by depositing a second conductive layer or a second conductive layer system and structuring them by means of a planarizing etching process, for example CMP.
• the lower segments of the second line and the second metallization level of the periphery are distinctive by Ab ⁇ and structuring of a third insulating layer and a third conductive layer or a drit ⁇ th conductive layer system, and the upper segments of the second line and the second contacts of the periphery by Deposition and structuring of a fourth insulating layer and a fourth conductive layer are formed.
• the production of the memory cell arrangement can be easily integrated into a multi-layer wiring process.
• Deposition steps and structuring steps are used which are required for the production of the peripheral metallization levels and the contacts required therebetween, also called via.
• the formation of the lower or upper segments of the first lines of the cell array in the same operation as the formation of the first metallization level (metal 1) or the first contact level (via 1) of the periphery.
• the lower or upper segments of the second lines are formed simultaneously with the second metallization level (metal 2) or the second contact level (via 2).
• This procedure also solves the technical problem that there is a much greater vertical distance between the metallization levels of the periphery arranged one above the other than between the first and the second lines of the cell array.
• the vertical distance between the first and second lines in the cell field is determined by the dimensions of the magnetoresistive element, which are typically 20 to 40 nm.
• the distance between adjacent metallization levels of the periphery must be much larger to reduce parasitic capacitances. at a 0.35 micron technology, it amounts to typically 350 to 400 nm.
• FIG. 1 shows a section through a memory cell arrangement with ring-shaped magnetoresistive elements and first line and second lines, each of which has first line parts that run parallel to the layer plane and second line parts that run perpendicular to the layer plane.
• FIG. 2 shows the section designated II-II in FIG.
• FIG. 3 shows a top view of a memory cell arrangement with magnetoresistive annular elements and first lines and second lines, the projections of which on the layer plane are strip-shaped bands.
• FIG. 4 shows a plan view of a memory cell arrangement with ring-shaped magnetoresistive elements and first lines and second lines, the projections of which on the layer plane are wavy, polygon-like bands.
• FIG. 5 shows the section designated VV in FIG. 4 through a magnetoresistive element and the adjacent regions of the associated first line and the associated second line.
• Figure 6 shows a section through a substrate having a first SiO 2 layer, a first layer and Si 3 N ei ⁇ ner second SiO 2 layer.
• FIG. 7 shows the section through the substrate after the formation of lower segments of first lines of the cell field and a first metallization level of the periphery.
• FIG. 8 shows the substrate after deposition and structuring of a second Si3N4 layer and a third
• FIG. 9 shows the substrate after the formation of first contacts of the periphery and upper segments of the first lines in the cell field.
• FIG. 10 shows the substrate after deposition of a first conductive barrier layer, a first ferromagnetic layer, a non-magnetic layer, a second ferromagnetic layer and a second conductive barrier layer.
• FIG. 11 shows the substrate after the formation of magnetoresistive elements by structuring the previously deposited layers using a self-aligned method based on spacer formation, which is explained with reference to FIGS. 20 to 22.
• FIG. 12 shows the substrate after the formation of a planarizing insulating layer.
• FIG. 13 shows the substrate after deposition and structuring of a third Si3N4 layer and a fourth SiO2 layer.
• FIG. 14 shows the substrate after structuring the fourth SiO 2 layer and the planarizing insulating layer.
• FIG. 15 shows the substrate after the formation of lower segments of second lines in the cell field and a second metallization level in the periphery.
• FIG. 16 shows the substrate after deposition and structuring of a fourth Si3N4 layer and a fifth
• FIG. 17 shows the substrate after the formation of upper segments of the second lines in the cell field and second contacts of the periphery.
• FIG. 18 shows the substrate after deposition and structuring of a fifth Si3 4 layer and a sixth SiO 2 layer.
• FIG. 19 shows the substrate after formation of a third metallization level.
• FIG. 20 shows a section through a substrate with an upper segment of the first line after deposition of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer, after deposition and structuring of an auxiliary layer and after deposition of a conformal layer.
• FIG. 21 shows the section through the substrate after anisotropic etching of the conformal layer, as a result of which a spacer-shaped mask is formed.
• FIG. 22 shows the substrate after removal of the structured auxiliary layer and after formation of magnetoresistive elements. elements by structuring the first ferromagnetic layer, the non-magnetic layer and the second ferromagnetic layer.
• FIG. 23 shows a magnetoresistive element with annular layer elements.
• ring-shaped magnetoresistive elements 11 are each arranged between a first line 12 and a second line 13 (see FIG. 1 and FIG. 2).
• the magnetoresistive elements have an annular cross section in a layer plane 14 which runs perpendicular to the plane of the drawing.
• the first lines 12 have first line parts 121 and second line parts 122.
• the first line parts 121 run parallel to the layer plane 14, the second line parts 122, however, perpendicular to the layer plane 14.
• the second lines 13 have first line parts 131 and second line parts 132.
• the first line parts 131 run parallel to the layer plane 14, the second line parts 132 vertically to the layer plane 14.
• a current flows through the first line 12 or through the second line 13, one predominates in parallel in the first line parts 121 and 131 the layer level 14 directed current component.
• a current component directed perpendicular to the layer plane 14 predominates.
• first lines and the second lines 13 are poled so that at the location of the intersection between one of the first lines 12 and one of the second lines 13 arranged magnetoresistive Element 11, the vertical current components flow in the respective second line portion 122, 132 m in the same direction, so there is a constructive superposition of these azimuthal magnetic fields and the magnetization of the magnetoresistive element 11 arranged in this crossing region can be switched over.
• first line portions 121, 131 and the second line portions 122, 132 results in the first lines 12 and the second lines 13 having a step-shaped cross section in a plane perpendicular to the layer plane 14.
• a memory cell arrangement has first lines 31 which run parallel to one another and second lines 32 which also run parallel to one another and which cross the first lines 31 (see FIG. 3).
• the first lines 31 and the second lines 32 each have a strip-shaped cross section. They have a width of 0.35 ⁇ m, a mutual distance of 0.35 ⁇ m and a length of approx. 70 to 700 ⁇ m depending on the cell area.
• a magnetoresistive element 33 with an annular cross section is arranged in each case. Since it is covered by the second line 32 in the view in FIG. 3, the contour of the magnetoresistive element 33 is shown in dashed lines in FIG.
• the first lines 31 and the second lines 32 have a section perpendicular to the plane of the drawing and parallel to the strip-shaped course, a step-shaped cross section with first line components that run parallel to the drawing plane and second line components that run perpendicular to the drawing plane, as shown in FIG 1 and 2 loading wrote.
• a current flows through the first conduit 31 and through the second conduit 32, so predominates m the first line portions each having a cut parallel to the annular cross ⁇ directed flow component.
• a current component directed perpendicular to the annular cross section predominates.
• Arranged above and below each of the magnetoresistive elements 33 is a second line component of the associated first line 31 and the associated second line 32, with which a current can flow perpendicular to the annular cross section of the magnetoresistive element 33.
• ring-shaped magnetoresistive elements 41 are arranged in a grid, m rows and columns, in a plane which is referred to as the layer plane (see FIG. 4).
• Each of the magnetoresistive elements 41 is arranged between a first line 42 and a second line 43.
• the projection of the first lines 42 and the second lines 43 onto the layer plane are in each case wavy, polygon-like bands which contain portions parallel to the respective row or column. These parallel portions are alternately staggered in parallel with respect to the straight line through the centers of adjacent magnetoresistive elements 41.
• the first lines 42 and the second lines 43 have a step-shaped cross section (see FIG. 5, m which is the section labeled VV in FIG. 4).
• the first line 42 has a first line part 421 and a second line part 422.
• the first line part 421 runs parallel to the drawing plane
• the second line part 422 runs perpendicular to the drawing plane.
• the second line 43 has a first line component 431, which runs parallel to the plane of the drawing.
• the second Lei ⁇ tung 43 further has a second line portion 432, which proceeds perpendicular to the plane.
• first line parts 421, 431 and second line parts 422, 432 are arranged along each of the first lines 42 and the second lines 43.
• a first layer of SiO 2 is 62 m with a layer thickness of 50 to 100 nm, a first layer of Si3N4 layer 63 m with a layer thickness of 30 to 50 nm and one second Si2 layer 64 m applied with a layer thickness of 400 to 800 nm (see FIG. 6).
• the second S ⁇ 2-Sch ⁇ cht 64 is structured to be opened m the second S ⁇ 2-Sch ⁇ cht trench 64 64 x.
• a first conductive diffusion bamer layer 65 made of TaN / Ta m with a thickness of 50 nm and a first conductive layer made of copper are deposited over the whole area.
• the first conductive layer of copper is deposited to such a thickness that it completely fills the trenches 64 times .
• the first conductive diffusion barrier layer 65 and the first conductive layer are structured by chemical mechanical polishing.
• the surface of the second S1O2 layer 64 is exposed and the lower segments 67 of the first line in the area of a first line embedded in the trenches 64 '
• Cell field Z and lines of a first metallization level 68 are generated in the area of a periphery P (see FIG. 7).
• a second Si3N4 layer 69 m thick from 30 to 50 nm and a third Si2 layer 610 m thick 400 to 800 nm thick are deposited using a photolithographically produced resist mask and anisotropic etching structured (see Figure 8).
• trench 610 are det ⁇ gebil ⁇ .
• a second conductive barrier layer 611 and a second conductive layer 612 are then deposited over the entire area .
• the second conductive barrier layer 611 is formed with a layer thickness of 50 nm from TaN / Ta.
• the second lei ⁇ tend layer is made of copper m thickness of such a layer deposited to fill the trench 610 ⁇ .
• the second conductive layer and the second conductive barrier layer 611 are planarized by CMP, so that the surface of the second Si 2 layer 610 is exposed and the trenches ⁇ embedded upper segments of the first line 613 and first contacts 614 are produced (see FIG. 9 ).
• the upper segments 613 of the first line and the lower segments 67 of the first line partially overlap.
• a first barrier layer 615, a first ferromagnetic layer 616, a non-magnetic layer 617, a second ferromagnetic layer 618 and a second diffusion barrier layer 619 are then deposited over the entire surface (see FIG. 10).
• the first diffusion barrier layer 615 and the second diffusion barrier layer 619 are formed from Ta in a layer thickness of 10 to 30 nm.
• the first ferromagnetic layer 616 is formed from Co in a layer thickness of 3 to 10 nm.
• the non-magnetic layer 617 is formed from Al 2 O 3 with a layer thickness of 1 to 3 nm.
• the second ferromagnetic layer 618 is formed with a layer thickness of 3 to 10 nm from NiFe.
• FIG. 10 shows the first ferromagnetic layer 616, the non-magnetic layer 617 and the second ferromagnetic layer 618 as a triple layer 616, 617, 618.
• magnetoresistive elements 621 are formed, which have an annular cross section parallel to the surface of the substrate 61 (see FIG. 11).
• the mask 620 is produced using a self-aligned process, which is explained below with reference to FIGS. 20 to 22.
• the magnetoresistive elements 621 are surrounded with insulating material by deposition and planarization with CMP of a fourth Si2 layer 622 (see FIG. 12).
• a third Si 3 N 4 layer 623 is subsequently deposited and structured using a photoresist mask 624 in such a way that the magnetoresistive elements 621 remain covered by the third Si 3 N layer 623, while this layer is removed in the region of the periphery (see FIG. 13 ).
• a fifth Si2 layer 625 m is deposited over the entire surface and has a thickness of 400 to 800 nm, on the surface of which a photoresist mask 626 is formed by photolithographic process steps.
• the fifth Si2 layer 625 and the fourth Si2 layer 622 are structured using the photoresist mask 626 as an etching mask. In this case, trenches are produced ⁇ 625 (see Figure 14).
• the third Si 3 N4 layer 623 remains above the magnetoresistive elements 621.
• a third conductive bar is centering layer 627 and depositing a third conductive layer, the ⁇ fill the trench 625 (see Figure 15).
• the third conductive barrier layer 627 is formed from Ta / TaN in a layer thickness of 30 to 50 nm.
• the third conductive layer is made of copper.
• the third conductive barrier layer 627 and the third conductive layer are planarized by chemical mechanical polishing.
• the surface of the fifth layer 625 is exposed.
• a second metallization level 630 is formed (see Figure 15).
• a fourth Si3N4 layer 631 m with a layer thickness of 30 to 50 nm and a sixth Si2 layer 632 m with a layer thickness of 400 to 800 nm are deposited over the entire surface.
• a mask 633 is then made of photoresist using photolithographic process steps.
• the sixth S1O2 layer 632 and the fourth Si3N4 layer 631 are structured by anisotropic etching, trenches 632 being formed (see FIG. 16).
• a fourth conductive barrier layer 634 and a fourth conductive layer are deposited on the flanks of the trenches 632 and fill the trenches 632 ⁇ .
• the fourth conductive barrier layer 634 is formed from TaN / Ta m with a layer thickness of 50 nm. The bottom of the trenches is exposed by sputtering and / or RIE processes.
• the fourth conductive layer is formed from copper with a layer thickness such that the trenches 632 are filled.
• the fourth conductive barrier layer 634 and the fourth conductive layer are planarized by CMP, the surface of the sixth layer 632 being exposed.
• second contacts 636 m of the periphery P and upper segments 637 of the second line in the cell field Z are formed from the fourth conductive layer (see FIG. 17).
• Photoresist mask and anistropic etching trenches 639 are opened, which extend to second contacts 636 (see FIG. 18).
• a fifth conductive barrier layer 640 made of Ta / TaN m with a layer thickness of 30 to 50 nm and a fifth conductive Layer of copper be ⁇ the trenches filled with a third metallization 642,639 (see Figure 19).
• a first ferromagnetic layer 72 made of Co in a layer thickness of 3 to 10 nm, a non-magnetic layer 73 made of Al 2 O 3 in a layer thickness of 1 to 3 nm and a are placed on a substrate 71 which has a diffusion barrier layer in the region of the surface second ferromagnetic layer 74 made of NiFe applied in a layer thickness of 3 to 10 nm (see FIG. 20).
• An auxiliary layer 75 made of Si 3 N4 is applied to the second ferromagnetic layer 74 in a thickness of 50 to 100 nm and structured using a photoresist mask (not shown). In this case, an opening is created in the auxiliary layer 75, in which the surface of the second ferromagnetic layer 74 is exposed.
• a conformal layer 76 of SiO 2 or Ta is formed in a layer thickness of 80 to 120 nm.
• RIE Anisotropic etching
• F- or Cl-containing reaction gases forms a spacer 77 from the conformal layer 76, which is ring-shaped due to the manufacturing process (see FIG. 21).
• the spacer 77 is removed after the structured
• Auxiliary layer 75 is used as an etching mask in order to structure the second ferromagnetic layer 74, the non-magnetic layer 73 and the first ferromagnetic layer 72 (possibly including diffusion barriers, not shown).
• An annular, magnetoresistive element 78 is formed in the process. If the spacer 77 was formed from Ta that has a diffusion barrier effect, it can be used as a diffusion barrier in the memory cell arrangement.
• a magnetoresistive element 81 which is an annular
• Cross-section comprises at least a first ferromagnetic layer element 82, a non-magnetic layer element 83 and a second ferromagnetic layer element 84, which are arranged as a stack one above the other.
• the first ferromagnetic layer element 82 has a layer thickness of 3 to 10 nm, an outer diameter of 350 nm and an inner diameter of 100 to 190 nm and contains Co.
• the non-magnetic layer element 83 has a thickness of 1 to 3 nm and contains Al2O3.
• the second ferromagnetic layer element 84 has a thickness between 3 and 10 nm and contains NiFe.
• the non-magnetic layer element 83 and the second ferromagnetic layer element 84 have the same cross section as the first ferromagnetic layer element.
• the first ferromagnetic layer element 82 and the second ferromagnetic layer element 84 can each have a magnetization in the clockwise or counterclockwise direction. If the magnetization of the first ferromagnetic layer element 82 coincides with that of the second ferromagnetic layer element 84 m, the magnetoresistive element 81 has a lower resistance than if the magnetizations of the first ferromagnetic layer element 82 and the second ferromagnetic layer element 84 are oriented in opposite directions.
• the second layer 64 layer 64 is deposited with a greater thickness (for example by a factor of 2 thicker). This creates deeper trenches 62 ′ and, after the CMP step, correspondingly thicker lower segments 67 of the first lines.
• a greater thickness for example by a factor of 2 thicker.
• the fourth Si2 layer 622 is produced by an anisotropic RIE process (for example using etching gases containing C and F). so that the magnetoresistive elements 621 are laterally isolated by SiO 2 spacers.
• the third Si3N4 layer 623 is then deposited as conformingly as possible.
• the fifth Si2 layer 625 is deposited for the lower segments of the second lines and planarized by a short CMP layer. Then the fifth Si2 layer 625 are selectively structured to form the third Si3N4 layer 623 and these are selectively structured to form the Si2 spacers of the fourth Si2 layer 622.

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• Engineering & Computer Science (AREA)
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• Semiconductor Memories (AREA)
• Mram Or Spin Memory Techniques (AREA)
• Hall/Mr Elements (AREA)
• Thin Magnetic Films (AREA)

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• 2000
  • 2000-02-01 EP EP00910521A patent/EP1155462B1/de not_active Expired - Lifetime
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